U.S. lawmakers are considering legislation that would legally protect journalists from revealing their confidential sources. The measure is gaining support in the wake of the imprisonment of a New York Times reporter who refused to reveal her sources in a federal investigation into the disclosure of a covert intelligence operative.

The Republican-sponsored Free Flow of Information Act was introduced in the House of Representatives and the Senate last January.

The legislation is getting renewed attention following the imprisonment of New York Times reporter Judith Miller for refusing to discuss her sources with federal prosecutors investigating the disclosure of Central Intelligence Agency operative Valerie Plame's identity. It is illegal to disclose a covert intelligence operative's name.

President Bush's top political adviser, Karl Rove, and Vice President Dick Cheney's chief of staff, Lewis Libby, are reported to be at the center of a federal investigation into who leaked the identity of Ms. Plame, whose diplomat husband, Joseph Wilson, challenged the administration's prewar intelligence on Iraq.

Reporter Judith Miller never wrote about Ms. Plame, but she was jailed for contempt of court for her unwillingness to testify about her sources. She was released late last month after spending 85 days in prison, saying Mr. Libby had released her from her obligation to keep his name and the contents of their conversation confidential.

Ms. Miller appeared before the Senate Judiciary Committee Wednesday to appeal for a so-called "federal shield law" to legally protect journalists from revealing their confidential sources.

"I am here because I hope you agree that an uncoerced, incoercible press, though at times irritating, is vital to the perpetuation of the freedom and democracy we so often take for granted," she said.

"Journalists should not be called to become witnesses for prosecutors, they should not be called to help prosecutors or other lawyers outside of the criminal courts to do their work," said Ms. Gordon. "We are not another arm of government. We are something quite distinct, and we need to be seen as such."

But the U.S. Justice Department opposes such legislation, saying it would hurt the government's ability to enforce the law, fight terrorism and protect national security.

Chuck Rosenberg is U.S. Attorney for the southern district in Texas.

"In the most urgent circumstances, [shield law legislation] prevents us from getting information quickly when we need it the most to protect the public," said Mr. Rosenberg.

Steven Clymer, a professor at Cornell Law School in New York, agrees.

"These laws are designed to safeguard information that if improperly disclosed, could jeopardize not only national security, but the safety of law enforcement officials, such as information about whether a search warrant is going to be executed, it could undermine criminal investigations and it could destroy the reputations of innocent people," said Mr. Clymer.

But the chairman of the Senate committee, Senator Arlen Specter, a Pennsylvania Republican, suggested there is a need for a shield law. His comments were directed at the New York Times' Judith Miller and the Philadelphia Inquirer's Anne Gordon, and other journalists who appeared before the panel.

"Your exposure of corruption and mismanagement and malfeasance is legendary," he said. "There is just no doubt about it. We want to be sure you are not harassed. We have countervailing considerations about being sure the criminal law can be enforced and national security interests are protected. But that is what we are here to do."